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No. 626,747. Patented lune I3, I899. A. P. BOABDMAN.

EXTENSION TABLE SLIDE.

(Application filed Aug. 6, 1897.)

(No Model.)

Mam raw NORRIS PETERS c0v PNOTO-LITNO WASHINGTON a c UNITED STATES PATENT OFFICE.

ANSON P. BOARDMAN, OF WATERTOWVN, WISCONSIN, ASSIGNOR TO THE BLAESIUS TABLE SLIDE COMPANY, OF SAME PLACE.

EXTENSION-TABLE SLIDE.

SPECIFICATION forming part of Letters Patent No. 626,747, dated June 13, 1899.

Application filed August 6, 1897.

To all whom, it may concern.-

Be it known that I, ANSON P. BOARDMAN, of \Vatertown,in the countyof Jefferson and State of Visconsin, have invented certain new and useful Improvements in Extension- Table Slides; and I do hereby declare that the following is a full, clear, and exact description of the invention, which will enable others skilled in the art to which it pertains to make and use the same, reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form a part of this specification.

My invention relates to that class of eX tension-table slides known as T-slides, in which the wooden slide-bars are provided with undercut grooves in their adjoining faces and with metallic plates or washers attached to the several bars, so as to engage with the grooves in the adjoining bars. Its main objects are to avoid binding and sticking, to take up play, to prevent the metallic washers from gouging into and mutilating the wooden slide-bars, and generally to improve the construction and operation of devices of this class.

It consists, essentially, of the convex metallic washers by which the slide-bars are held together face to face and of the means for attaching them to the slide-bars. I

In the accompanying drawings like letters designate the same parts in the several figures.

Figure 1 is a cross-section on the line 1 1, Fig. 2, of two slide-bars to which my improvements are applied. Fig. 2 is a side elevation of a portion of a slide-bar to which the metallic washer is attached; and Fig. 3 is a longitudinal section thereof on the line 3 3, Fig. 2.

A A designate the wooden bars of an extension-table slide, which may be made up of any number of said bars, according to the size of the tables to which they are to be applied or to what extent it is desired to make them extensible. Each of these bars is formed in one or both faces with a longitudinal undercut or T-shaped groove C6 of a common form in table-slides of this kind. The outer bars A of each slide have a groove in one side only, while the intermediate bars A have corresponding grooves in both sides. One

Serial No. 647,277. (No model.)

end of each groove in each slide-bar is filled or provided with a block 13, preferably made to fit the groove, as shown in Fig. l, and projecting therefrom, -so as to enter the groove in the adjoining bar, as shown inFigs. 1 and 3. The projecting portion of each of these blocks is fitted between and is made of the same thickness as the inturned overhanging edges of the groove in the adjoining slide-bar. To each of these blocks is attached a substantially circular and semispherical or concavo-convex rigid metallic plate or washer (J by a screw 0 passing centrally through it into the block, the convex side being placed next to the block, which is countersunk around the screw-hole, as shown in Figs. 1 and 3, to form a seat and firm support for the washer around and at a distance from the screw. Between the concave side of the washer and the screw-head is interposed a spring-plate D, centrally perforated to receive the screw and having radial arms bearing at their outer ends against the washer at or near its periphery. The washer is thus yieldingly attached to the slide-bar, so that in traversing the groove in the adjoining bar it will readily adapt itself to any variations or inequalities'in the overhanging edges of the groove, and thus prevent binding and sticking. The convex side of the washer being presented to and bearing against the inturned edges of the groove prevents the edges of the washer from coming in contact with and gouging into or mutilating the slide-bar. The slides are thus made to work easily under all conditions and may be made and adjusted to run with little play between the faces of the adjoining bars.

The plates or washers 0 being of circular form and centrally attached to the slide-bars and having convex bearing-faces, they each require but one fastening, as it does not affeet their operation if they turn on the screws 0. In whatever position they may be attached to the slide-bars or whatever position they may afterward assume by turning they will present rounded bearing-faces to the inwardly-extending tongues on either side of the grooves in which they work and their edges cannot come into contact with the tops, bottoms, or sides of the grooves. As extension-table slides are subjected to severe usage, particularly if they stick and work hard, a simple connection between the slide-bars, like that herein shown and described, which cannot get out of operative adjustment and which will work with certainty and freedom under all conditions, is a great desideratum.

' In place of the screws 0 pins or nails may obviously be used. I prefer the screws, however, since with them the tension of the springsD can be more easily and satisfactorily adjusted.

Various changes in details of construction maybe made within the spirit and intended scope of my invention. The advantages of my improvements might be secured to a cer tain extent by the use of convex metallic washers Without the springs, or by the use of i the springs or yielding fastenings with flat instead of convex washers; but while I wish to cover each of the features independently, of the other their employment together is essential to the attainment of thebest results.

I claim- 1. In an extension-table slide the combination of wooden slide-bars having undercut grooves in their adjoining faces, and an ap- 1 proximately circular semispherical metal plate or washer centrally attached to each bar Withits convex face toward said bar so as to engage and run in the groove of the adjoin- 1 ing bar, substantially as and for the purposes set forth. 1

2. In an extension-table slide the combina- 1 tion of slide-bars having undercut grooves in their adjoining faces, and a rigid semispherical circular plate or washer yieldingly and centrally attached to each bar with its convex face toward said bar and engaging with the groove in the adjoining bar, substantially as and for the purposes set forth.

3. In an extension-table slide the combination of slide-bars having undercut grooves in their adjoining faces, an approximately circular ooncavo-convex washer centrally attached to each bar by a screw or pin, and engaging on its convex face with inturned sides of the groove in the adjoining bar, and a spring interposed between the head of said screw or pin and the concave side of the washer, substantially as and for the purposes set forth.

4. In an extension-table slide the combination of slide-bars having undercut grooves in their adjoining faces, an approximately circular concave-convex washer attached to each bar by ascrew or pin passing centrally through the washer, and aeentrally-perforated springplate interposed between the concave side of said washer and the head of said screw or pin and having arms extending outwardly therefrom and bearing against said washer at or near its periphery, substantially as and for the purposes set forth.

In testimony that I claim the foregoing as my own I affix my signature in presence of two witnesses. v

ANSON P. BOARDMAN.

Witnesses:

H. J ACOBI, M. H. GAEBLER. 

